Our project aims to implement the emerging nodejs technique (the server side javascript) as a lightweight web server on the beagleboard and accomplish a series of remote monitoring and control of hardware pins like gpio/led/i2c on the beagleboard. There are a lot of things we can do on the nodejs web server, but we try to make it related to our beagleboard hardware interface.

+

Very well done. I had no trouble '''git'''ting your files and running the code. It works! Your documentation is very good. I'm able to follow what you did.

−

Give two sentences telling what isn't working.

+

Some things I want to try are:

+

# Have the current LED trigger selected on the web page.

+

# Have the new temperature pushed to the page rather than have the page keep polling.

+

# Only update the part of the page that needs updating.

−

End with a two sentence conclusion.

+

Wiki: 95

+

Project: 95

+

'''Total:''' 95

−

The sentence count is approximate and only to give an idea of the expected length.

+

== Executive Summary ==

+

+

Our project aims to implement the emerging node.js technique (the server side javascript) as a lightweight web server on the beagleboard and accomplish a series of remote monitoring and control of hardware pins like gpio/led/i2c on the beagleboard. We also tried to make our web server send automatic email when temperature goes too high. There are a lot of things we can do on the node.js web server, but we try to make it related to our beagleboard hardware interface.

+

+

The automatic email sender is not working correctly. More work needs to be done to set a proper configuration to the SMTP server 'postfix'.

+

+

This turns out to be a very fun application-level project and node.js is really a very friendly, easy-to-use emerging technology that should be promoted to wider industry use.

== Installation Instructions ==

== Installation Instructions ==

Line 18:

Line 29:

2. Additional packages installed via '''opkg''':

2. Additional packages installed via '''opkg''':

−

* install nodejs

+

* install node.js

−

<pre>

+

−

opkg update

+

−

opkg install nodejs

+

−

opkg install nodejs-dev

+

−

</pre>

+

−

* install node package manager

+

beagle$ '''opkg update'''

−

<pre>

+

beagle$ '''opkg install nodejs''' (about a minute)

−

curl http://npmjs.org/install.sh | sh

+

beagle$ '''opkg install nodejs-dev''' (about a minute)

−

</pre>

+

+

* install curl and the node package manager

+

+

beagle$ '''opkg install curl''' (about a 1 minute to install)

+

beagle$ '''curl http://npmjs.org/install.sh | sh''' (about a minute)

* install socket.io module

* install socket.io module

−

<pre>

+

−

npm install socket.io

+

beagle$ '''npm install socket.io''' (45 seconds, but I get an error)

−

</pre>

+

* install binary module

* install binary module

+

+

beagle$ '''npm install binary''' (30 seconds)

+

+

* install mailer module

+

+

beagle$ '''npm install mailer''' (5 seconds)

+

+

* install SMTP server postfix

+

Go to [http://postfix.energybeam.com/source/index.html] download the source of postfix, then unzip the .gz file, then run 'make', then run

<pre>

<pre>

−

npm install binary

+

sh postfix-install

</pre>

</pre>

−

* Include kernel mods.

−

* If there is extra hardware needed, include links to where it can be obtained.

Once everything is installed, how do you use the program? Give details here, so if you have a long user manual, link to it here.

+

Go to our github address above, our final work resides in the "/Project/new" [https://github.com/caoy1/Project/tree/master/new directory]. Pull everything out in that folder, then go into this "new" directory on your host computer, executes the index.js program, then you are good to go:

+

<pre>

+

node index.js

+

</pre>

+

On the console, "Server has started" will be printed out.

+

Fire up any of your browser, and visit the beagleboard's IP address:3001(port number). Currently the address is:

+

<pre>

+

http://137.112.101.67:3001

+

</pre>

+

The webpage will show up and the temperature is real-time updated. You can also select the LED toggle mode on the page, and when you hit "select", the LED light on the board will toggle in the way you specify on the page.

== Highlights ==

== Highlights ==

−

Here is where you brag about what your project can do.

+

Remote monitoring parameters like room temperature, if sensors are equipped on board, and control hardware pins on board, at anywhere, anytime, when you have access to the Internet.

−

+

−

Consider including a [http://www.youtube.com/ YouTube] demo.

+

== Theory of Operation ==

== Theory of Operation ==

−

−

Give a high level overview of the structure of your software. Are you using GStreamer? Show a diagram of the pipeline. Are you running multiple tasks? Show what they do and how they interact.

−

To build a web server, we need, in essence, both client side and server side scripts. Client side scripts mainly just involve ordinary javascripts that can be embedded in HTML file; while at the server-side, we adopt the emerging node.js, which is a really simple server side script that accomplishes equivalent tasks like ASP, PHP will do, but with even simpler implementation details.

To build a web server, we need, in essence, both client side and server side scripts. Client side scripts mainly just involve ordinary javascripts that can be embedded in HTML file; while at the server-side, we adopt the emerging node.js, which is a really simple server side script that accomplishes equivalent tasks like ASP, PHP will do, but with even simpler implementation details.

== Work Breakdown ==

== Work Breakdown ==

Line 66:

Line 86:

<pre>

<pre>

−

fs.writeFileSync("/sys/class/gpio/export", ""+5);

+

fs.writeFileSync("/sys/class/gpio/export", "+5");

</pre>

</pre>

Line 73:

Line 93:

a) To translate tons of the C codes into JavaScript...including rewriting the union structures like i2c_smbus_write_byte() and i2c_smbus_read_byte(), which requires far more knowledge in understanding how to translate the underlying hardware detail into upper-level script languages...

a) To translate tons of the C codes into JavaScript...including rewriting the union structures like i2c_smbus_write_byte() and i2c_smbus_read_byte(), which requires far more knowledge in understanding how to translate the underlying hardware detail into upper-level script languages...

* It seems that the second way is easier... We've already found a ActiveXObject.run method... We're working on this... turns out this does not work for some reason.

* It seems that the second way is easier... We've already found a ActiveXObject.run method... We're working on this... turns out this does not work for some reason.

Line 125:

Line 145:

4. The next thing we will do is to refresh the website every other time...

4. The next thing we will do is to refresh the website every other time...

−

* We are now able to load html file inside nodejs scripts so that we can put normal HTML stuff inside the web page and load it from server scripts. The following code snippet can accomplish this (borrowed and modified based on Jadon's code):

+

* We are now able to load html file inside node.js scripts so that we can put normal HTML stuff inside the web page and load it from server scripts. The following code snippet can accomplish this (borrowed and modified based on Jadon's code):

<pre>

<pre>

function loadHTMLFile(uri, res, temp) {

function loadHTMLFile(uri, res, temp) {

Line 195:

Line 215:

</html>

</html>

</pre>

</pre>

+

+

5. Now we are trying to do something fancy! We want to send the user an automatic warning email when the temperature is too high. Here's the Javascript code using node.js mailer module. This code use SMTP server to send email to the destination.

+

+

<pre>

+

var email = require('mailer');

+

+

email.SMTP = {

+

host: 'smtp.gmail.com',

+

port: 587,

+

ssl: false,

+

use_authentication: false,

+

}

+

+

email.send({

+

to : "caoy1@rose-hulman.edu",

+

from : "obama@whitehouse.gov",

+

subject : "I love beagleboard!",

+

body: "Hello beagle world.",

+

},

+

+

function(err, result) {

+

if(err) {

+

console.log(err);

+

}

+

});

+

</pre>

+

+

* However, the configuration on our beagle has some problem. The server has no response to mailer's request. We've tried telnet localhost 587, and connection can be connected. This means the 587 port is already opened. Then I tried the same code under my ubuntu system, it turns out everything works fine, the caoy1@rose-hulman.edu can receive the e-mail, except some client-side warning error when running the mail.js file. I think the reason it works on ubuntu is because when installing postfix, there's an automatic configuration step, which doesn't exist on our beagle installation. So there must be some problem with the postfix configuration of beagleboard. I've tried to copy all the configuration files under /etc/postfix to our beagleboard, but there's just the same problem. If I have more time, or someone else who's interested in continuing this project, I suggest you have some research on the configuration thing. Everytime you make some config changes, just run

+

<pre>

+

postfix reload

+

</pre>

+

to apply the change.

+

+

5. Our next goal is to toggle LED via web page, whose control flow structure is essentially similar to the i2c communications, plus, we have already learned the way to write to the led pin via node.js script(see note1 above).

+

* Before actually doing that, let's first organize our code in a more hierarchical and reasonable way.Thanks to Mr. Manuel Kiessling's excellent introductory tutorial "[http://www.nodebeginner.org The Node Beginner Book]", which gives a pretty decent explanation on how a formal web server architecture should be constructed using node.js. Basically, we should maintain an index.js that starts all of our code, have a server.js to actually create the server and listen on the port for any posts from the client side, and pass the request and response to the router.js to handle different requests. In requestHandlers.js, each function then does the real work based on the request information and execute corresponding server responses.

+

* The following is what's in index.js:

+

<pre>

+

var server = require("./server");

+

var router = require("./router");

+

var requestHandlers = require("./requestHandlers");

+

+

var handle = {}

+

handle["/"] = requestHandlers.i2c;

+

handle["/led"] = requestHandlers.led;

+

handle["/i2c"] = requestHandlers.i2c;

+

+

server.start(router.route, handle);

+

</pre>

+

* And we abstract the server.js to be a general form so that it is independent of what will actually be done at the server, such details are left for requestHandlers.js to accomplish:

+

<pre>

+

var http = require("http");

+

var url = require("url");

+

var sys = require('sys');

+

var fs = require('fs');

+

var path = require('path');

+

var events = require('events');

+

+

function start(route, handle) {

+

function onRequest(request, response){

+

var pathname = url.parse(request.url).pathname;

+

route(handle, pathname, response, request);

+

}

+

+

http.createServer(onRequest).listen(3001);

+

console.log("Server has started.");

+

}

+

+

exports.start = start;

+

</pre>

+

* router.js gets the request's pathname and call different functions according to different request url:

+

<pre>

+

function route(handle, pathname, response, request) {

+

console.log("About to route a request for " + pathname);

+

if (typeof handle[pathname] === 'function') {

+

handle[pathname](response, request);

+

} else {

+

console.log("No request handler found for " + pathname);

+

response.writeHead(404, {"Content-Type": "text/plain"});

+

response.write("404 Not found");

+

response.end();

+

}

+

}

+

+

exports.route = route;

+

</pre>

+

* In requestHandlers.js, we need two functions, one for handle i2c request, another for led toggling request:

+

<pre>

+

function i2c(response, request) {

+

var uri = url.parse(request.url).pathname;

+

...//same as described above, including calling loadHTMLFile function that's also in requestHandlers.js

+

}

+

+

function led(response, request) {

+

...//details in below

+

}

+

</pre>

+

+

6. Now it's time for us to think about how to toggle LED via web page. Turns out it's very similar to how i2c works. However, this time we need to not only parse the uri of the request, but also get the posted data from the request, parse them and write them into the appropriate file system. The event-driven node.js utilizes "addListener" function to achieve the task, with parameter "data" to receive the data and "end" to handle and process them. The data received(in type of string) should be converted to object class by the "querystring" module.

+

+

On the client side, we use exclusive radio button to allow user to choose the toggle mode of LED:

+

<pre>

+

<form action = "/led" method="post" size="30">

+

<input type="radio" name="mode" value="nand-disk" >nand-disk

+

<input type="radio" name="mode" value="mmc0" />mmc0

+

<input type="radio" name="mode" value="heartbeat" >heartbeat

+

<input type="radio" name="mode" value="none" >none

+

<input type="submit" value="Select" onclick="xmlhttpPost()">

+

</form>

+

</pre>

+

The corresponding javascript just submits this form to /led, which then be handled by router to execute led() function:

Another thing to notice is, in order for this requestHandler for led.js not to jump to a brand new web page but stay on the current one, the normal "request.end()" code, which indicates the completion of an intact .js page, should be left out.

+

+

7. Eventually we did a little bit beautification on the html page --- somehow CSS does not work as intended, we simply change some font and color of the output to make it a bit neater.

+

== Conclusions ==

== Conclusions ==

−

Give some concluding thoughts about the project. Suggest some future additions that could make it even more interesting.

+

This project dabbles in the possibility of setting a web-server written in node.js on the embedded environment and accomplishes the proposed idea of interacting with underlying hardware pins and system via upper-level user interface. node.js is very simple and easy to implement, its non-blocking, event-driven and single-threaded mechanism is exactly suitable for the embedded system and our project gives a good instance of its application. Our demo system can be scaled up with far more features in remote monitoring and smart control industry. If, for example, the nodemailer can work well on the Angstrom (apparently it's working on Ubuntu, but somehow does not seem to be compatible with Angstrom), or other embedded Linux distribution, it can become as powerful as intelligent agent in monitoring various parameters, like temperature, moisture, so on so forth.

Latest revision as of 05:57, 16 July 2012

Contents

Grading

Very well done. I had no trouble gitting your files and running the code. It works! Your documentation is very good. I'm able to follow what you did.

Some things I want to try are:

Have the current LED trigger selected on the web page.

Have the new temperature pushed to the page rather than have the page keep polling.

Only update the part of the page that needs updating.

Wiki: 95
Project: 95
Total: 95

Executive Summary

Our project aims to implement the emerging node.js technique (the server side javascript) as a lightweight web server on the beagleboard and accomplish a series of remote monitoring and control of hardware pins like gpio/led/i2c on the beagleboard. We also tried to make our web server send automatic email when temperature goes too high. There are a lot of things we can do on the node.js web server, but we try to make it related to our beagleboard hardware interface.

The automatic email sender is not working correctly. More work needs to be done to set a proper configuration to the SMTP server 'postfix'.

This turns out to be a very fun application-level project and node.js is really a very friendly, easy-to-use emerging technology that should be promoted to wider industry use.

User Instructions

Go to our github address above, our final work resides in the "/Project/new" directory. Pull everything out in that folder, then go into this "new" directory on your host computer, executes the index.js program, then you are good to go:

node index.js

On the console, "Server has started" will be printed out.
Fire up any of your browser, and visit the beagleboard's IP address:3001(port number). Currently the address is:

http://137.112.101.67:3001

The webpage will show up and the temperature is real-time updated. You can also select the LED toggle mode on the page, and when you hit "select", the LED light on the board will toggle in the way you specify on the page.

Highlights

Remote monitoring parameters like room temperature, if sensors are equipped on board, and control hardware pins on board, at anywhere, anytime, when you have access to the Internet.

Theory of Operation

To build a web server, we need, in essence, both client side and server side scripts. Client side scripts mainly just involve ordinary javascripts that can be embedded in HTML file; while at the server-side, we adopt the emerging node.js, which is a really simple server side script that accomplishes equivalent tasks like ASP, PHP will do, but with even simpler implementation details.

2. Even though we can access to the gpio in the above way, we still need to find someway to access the I2C information. In the I2C exercises, from the C code provided in exercise 5, we can think of the following two options:

a) To translate tons of the C codes into JavaScript...including rewriting the union structures like i2c_smbus_write_byte() and i2c_smbus_read_byte(), which requires far more knowledge in understanding how to translate the underlying hardware detail into upper-level script languages...

4. The next thing we will do is to refresh the website every other time...

We are now able to load html file inside node.js scripts so that we can put normal HTML stuff inside the web page and load it from server scripts. The following code snippet can accomplish this (borrowed and modified based on Jadon's code):

Now we can update the temperature information on the website, both triggered by a button on the page, and by just automatically refreshing the temperature value whenever the temperature changes. Here is the simple client script for accomplishing this:

5. Now we are trying to do something fancy! We want to send the user an automatic warning email when the temperature is too high. Here's the Javascript code using node.js mailer module. This code use SMTP server to send email to the destination.

However, the configuration on our beagle has some problem. The server has no response to mailer's request. We've tried telnet localhost 587, and connection can be connected. This means the 587 port is already opened. Then I tried the same code under my ubuntu system, it turns out everything works fine, the caoy1@rose-hulman.edu can receive the e-mail, except some client-side warning error when running the mail.js file. I think the reason it works on ubuntu is because when installing postfix, there's an automatic configuration step, which doesn't exist on our beagle installation. So there must be some problem with the postfix configuration of beagleboard. I've tried to copy all the configuration files under /etc/postfix to our beagleboard, but there's just the same problem. If I have more time, or someone else who's interested in continuing this project, I suggest you have some research on the configuration thing. Everytime you make some config changes, just run

postfix reload

to apply the change.

5. Our next goal is to toggle LED via web page, whose control flow structure is essentially similar to the i2c communications, plus, we have already learned the way to write to the led pin via node.js script(see note1 above).

Before actually doing that, let's first organize our code in a more hierarchical and reasonable way.Thanks to Mr. Manuel Kiessling's excellent introductory tutorial "The Node Beginner Book", which gives a pretty decent explanation on how a formal web server architecture should be constructed using node.js. Basically, we should maintain an index.js that starts all of our code, have a server.js to actually create the server and listen on the port for any posts from the client side, and pass the request and response to the router.js to handle different requests. In requestHandlers.js, each function then does the real work based on the request information and execute corresponding server responses.

6. Now it's time for us to think about how to toggle LED via web page. Turns out it's very similar to how i2c works. However, this time we need to not only parse the uri of the request, but also get the posted data from the request, parse them and write them into the appropriate file system. The event-driven node.js utilizes "addListener" function to achieve the task, with parameter "data" to receive the data and "end" to handle and process them. The data received(in type of string) should be converted to object class by the "querystring" module.

On the client side, we use exclusive radio button to allow user to choose the toggle mode of LED:

Another thing to notice is, in order for this requestHandler for led.js not to jump to a brand new web page but stay on the current one, the normal "request.end()" code, which indicates the completion of an intact .js page, should be left out.

7. Eventually we did a little bit beautification on the html page --- somehow CSS does not work as intended, we simply change some font and color of the output to make it a bit neater.

Conclusions

This project dabbles in the possibility of setting a web-server written in node.js on the embedded environment and accomplishes the proposed idea of interacting with underlying hardware pins and system via upper-level user interface. node.js is very simple and easy to implement, its non-blocking, event-driven and single-threaded mechanism is exactly suitable for the embedded system and our project gives a good instance of its application. Our demo system can be scaled up with far more features in remote monitoring and smart control industry. If, for example, the nodemailer can work well on the Angstrom (apparently it's working on Ubuntu, but somehow does not seem to be compatible with Angstrom), or other embedded Linux distribution, it can become as powerful as intelligent agent in monitoring various parameters, like temperature, moisture, so on so forth.